Power distributor unit having an electromechanical switching assembly, and method for switching the power distributor unit

Abstract

The invention relates to a power distributor unit (16) having an electromechanical switching assembly (1) with at least one first electrical connection region (2) and at least one second electrical connection region (3), wherein the first electrical connection region (2) has at least one fixed first electrical contact element (4a-4g), the second electrical connection region (3, 3') has at least one fixed second electrical contact element (5a-5g), and the first electrical contact element (4a-4g) and the second electrical contact element (5a-5g) can be electrically connected and disconnected via at least one movable third electrical contact element (6a-6g). The power distributor unit also has a high-voltage battery (17), a first connection point (20) for the electrical drive and for a plurality of loads of the motor vehicle, the first connection point being connected to the first electrical connection region (2), and a second connection point (21), which is connected to the second connection region (3) of the switching assembly (1), the second connection point being electrically connected to a charging infrastructure. The power distributor unit is characterized in that at least one relay (22) switches the electrical connection between the first connection point (20) or the high-voltage battery (17) and the first connection region (2).

Description

[0001] Power distribution unit with electromechanical switching arrangement and method for switching the power distribution unit

[0002] The present invention relates to a power distribution unit with an electromechanical switching arrangement having at least one first electrical connection area and at least one second electrical connection area, wherein the first electrical connection area has at least one fixed first electrical contact element and the second electrical connection area has at least one fixed second electrical contact element, wherein the first electrical contact element and the second electrical contact element are electrically connectable and disconnectable via at least one movable third electrical contact element, and is connected to a high-voltage battery and a first connection point for the electric drive and several consumers of the motor vehicle, the first electrical connection area and a second connection point are connected to the second connection area of ​​the switching arrangement, which is electrically connected to a charging infrastructure.

[0003] State of the art

[0004] Power distribution units for motor vehicles, especially for hybrid or electric vehicles, have, in addition to fuse units and voltage and current measuring systems, switching arrangements that prevent or enable the flow of electricity through an electrical circuit of the vehicle.

[0005] These switching arrangements typically consist of at least three relays – depending on the design, at least two high-current relays and one pre-charging relay are used. Additional relays may be used for switching on and off.

[0006] 2024P00065 WO drive units, DC charging contacts, a battery bank switching system, and other functions are installed.

[0007] The relays used each consist of a contact and an actuator, which are controlled by corresponding output stages of a control unit and monitored via specific circuits.

[0008] The use of multiple individual relays and actuators results not only in high costs, but also in increased installation space requirements and weight. Furthermore, the relays themselves typically have two high-current connections that can only be passively cooled via the connected busbars. This negatively impacts the installation space and weight of the contact technology. The requirements for current carrying capacity and opening / closing speed also necessitate adjustments to the actuators. This negatively affects the overall weight, volume, and energy efficiency. Additionally, complex control and monitoring systems are required for each individual relay to detect and prevent malfunctions. The sum of all these disadvantages necessitates an improved switching arrangement suitable for use in a power distribution unit of a battery-electric vehicle.

[0009] The high-voltage relays used are generally identical in construction and each consists of a contact and an actuator, which are controlled by corresponding output stages of a control unit and monitored via specific circuits. Each of these relays has the necessary technology integrated to interrupt the current flow even under load.

[0010] A switching arrangement is known from the still unpublished DE 10 2023 209 219.

[0011] 2024P00065 WO The use of multiple individual relays results in a large installation space requirement and high weight. The identical design of the relays and the associated requirements for load isolation within the overall system mean that each individual high-voltage relay must have the necessary closing and opening speeds and therefore requires high-performance actuation coils. This negatively impacts the overall weight, volume, and energy efficiency. Additionally, complex control and monitoring systems are required for each individual relay to prevent and detect malfunctions, such as welded relays or asynchronous switching. This contributes to the high overall costs of battery-electric vehicles.

[0012] It is an object of the invention to provide an improved electromechanical switching arrangement, wherein the load case of switching on and off is reduced to a relay.

[0013] Summary of the invention

[0014] This problem is solved by the subject matter of the present invention according to independent claims 1 and 5. Advantageous embodiments of the present invention are described in the dependent claims.

[0015] The present invention reduces the load-case switching on and off to a single relay. The remaining necessary electrical preconditions are switched without a load via a switching matrix. The switching matrix therefore eliminates the need for any arc quenching devices.

[0016] An architecture is created with a switching arrangement as a passive switching element for the desired current flows and at least one relay for actively switching the current path on and off.

[0017] 2024P00065 WO The problem is solved by a power distribution unit with an electromechanical switching arrangement having at least one first electrical connection area and at least one second electrical connection area, wherein the first electrical connection area has at least one fixed first electrical contact element and the second electrical connection area has at least one fixed second electrical contact element, wherein the first electrical contact element and the second electrical contact element are electrically connectable and disconnectable via at least one movable third electrical contact element, and connected to a high-voltage battery and a first connection point for the electric drive and several consumers of the motor vehicle, the first electrical connection area and a second connection point are connected to the second connection area of ​​the switching arrangement.which is electrically connected to a charging infrastructure, wherein at least one relay switches the electrical connection between the first connection point or the high-voltage battery and the first connection area.

[0018] In one embodiment, the high-voltage battery is designed in two parts.

[0019] The power distribution unit is designed such that the third electrical contact element is biased into a switching position via at least one elastic element and can be actuated into at least one other switching position via an actuator unit, wherein the actuator unit has at least one actuator and at least one switching shaft which is movable via the actuator and, depending on the actuated switching position, either leaves the third electrical contact element in the biased switching position or moves it against the spring force of the elastic element into at least one other switching position.

[0020] Only at least one relay switches under load, while the contact elements of the switching arrangement are unloaded.

[0021] 2024P00065 WO With the solution according to the invention, it is possible to design the relays of the switching arrangement in a simpler and more cost-effective manner, while only the relays that switch under load have a higher quality specification and are therefore also more expensive.

[0022] The problem is also solved with a method for switching a power distribution unit, whereby the necessary / required electrical connections are made in the switching arrangement, and only when the relevant electrical contacts are switched is the relay closed and the circuit closed.

[0023] To interrupt the circuit, the sequence is reversed: first the relay is opened, and then the contacts of the switching arrangement are switched.

[0024] Brief description of the drawings

[0025] The invention is described below by way of example with reference to the drawings.

[0026] Fig. 1 shows a schematic top view of an electromechanical switching arrangement without a housing.

[0027] Fig. 2 shows a sectional view along the section plane AA according to Fig. 1 with a housing, wherein a third contact element is in a second switching position (open position).

[0028] Fig. 3 schematically shows a first embodiment of a power distribution unit according to the invention with an electromechanical switching arrangement.

[0029] 2024P00065 WO Fig. 4 schematically shows a second embodiment of a power distribution unit according to the invention with an electromechanical switching arrangement.

[0030] Detailed description of the invention

[0031] The invention is based on a switching arrangement, which is described by way of example with Figures 1 and 2.

[0032] Figures 1 and 2 show a first embodiment of the electromechanical switching arrangement 1. The electromechanical switching arrangement 1 has a first electrical connection area 2 and a second electrical connection area 3.

[0033] The first electrical connection area 2 and the second electrical connection area 3 are arranged side by side on a cooling unit 13 in a first assembly level X.

[0034] The first electrical connection area 2 has several fixed first electrical contact elements 4a-4g, namely seven first electrical contact elements 4a-4g.

[0035] The second electrical connection area 3 has several fixed second electrical contact elements 5a-5g, namely seven second electrical contact elements 5a-5g.

[0036] Each first electrical contact element 4a-4g of the first electrical connection area 2 is connected via a respective third contact element 6a-6g to a respective second electrical contact element 5a-5g of the second connection area.

[0037] 2024P00065 WO End area 3 connectable and separable.

[0038] The respective third contact element 6a-6g can be controlled via an actuator unit 8 in two switching positions A, B, namely in a first switching position A and in a second switching position B.

[0039] In the embodiment according to Fig. 1 and Fig. 2, the first switching position A corresponds to a switching position in which a respective first electrical contact element 4a-4g is electrically connected via a respective third electrical contact element 6a-6g to a respective second electrical contact element 5a-5g.

[0040] In the embodiment according to Fig. 1 and Fig. 2, the second switching position B corresponds to a switching position in which a respective first electrical contact element 4a-4g is electrically separated from the respective second electrical contact element 5a-5g.

[0041] The actuator unit 8 comprises an actuator 9, which is designed as an electric motor 9a, and a switching shaft 10 with several switching elements 11, namely seven switching elements 11. The switching shaft 10 is designed as a camshaft 10a and the individual switching elements 11 of the switching shaft 10 are formed by cams fixed on the camshaft 10a.

[0042] Each switching element 11 of the switching shaft 10 is functionally assigned to a third electrical contact element 6a-6g.

[0043] The switching shaft 10 is also arranged in the first assembly plane X in an area between the first electrical connection area 2 and the second electrical connection area 3 and extends axially between the two electrical connection areas 2, 3.

[0044] 2024P00065 WO The direction “axial” means a direction along or parallel to the central longitudinal axis 12 of the switching shaft 10.

[0045] The first electrical connection area 2 and the second electrical connection area 3 are partially arranged in a housing 14, such that the first electrical contact elements 4a-4g and the second electrical contact elements 5a-5g are arranged inside the housing 14 and connection points 20 of the respective electrical connection area 2, 3 are formed outside the housing 14.

[0046] Each connection point 20 is electrically connected to at least one respective first or second electrical contact element 4a-4g, 5a-5g of the respective connection area 2, 2', 3, 3'.

[0047] The switching shaft 10 is essentially mounted in the housing 14 and is rotatably driven by the electric motor 9a located outside the housing 14.

[0048] The third electrical contact elements 6a-6g are arranged in a second assembly level Y on an inner wall 15 of the housing 14 via two elastic elements 7, namely compression springs 7a in the present case, such that a third electrical contact element 6a-6g is arranged essentially parallel to the two electrical connection areas 2, 3 with their respective electrical contact elements 4a-4g, 5a-5g.

[0049] The second assembly level Y corresponds to a spatial plane parallel to the first assembly level X.

[0050] 2024P00065 WO The third electrical contact elements 6a-6g and the camshaft 10a are arranged such that each cam of the camshaft 10a can control each third electrical contact element 6a-6g into the two switching positions A, B.

[0051] In the first switching position A, each first electrical contact element 4a-4g is electrically connected to each second electrical contact element 5a-5g via each third electrical contact element 6a-6g. In the first embodiment shown in Fig. 1 and Fig. 2, this is achieved by biasing each third contact element 6a-6g radially towards its respective first electrical contact element 4a-4g and its respective second electrical contact element 5a-5g via the springs 7a, thus biasing it into a closed position.

[0052] In the second switching position B, each first electrical contact element 4a-4g is electrically separated from the respective second electrical contact element 5a-5g by moving the associated respective third contact element 6a-6g radially against the spring force of the springs 7a towards the inner wall 15 of the housing 14 via the cam of the camshaft 10a associated with it, thus effecting an open position.

[0053] In the first switching position A, each first electrical contact element 4a-4g is electrically connected to each second electrical contact element 5a-5g via each third electrical contact element 6a-6g. In the fourth embodiment shown in Figs. 5 and 6, this is achieved by biasing each third contact element 6a-6g radially towards its respective first electrical contact element 4a-4g and its respective second electrical contact element 5a-5g via the springs 7a, thus biasing it into a closed position.

[0054] 2024P00065 WO In the second switching position B, each first electrical contact element 4a-4g is electrically separated from the respective second electrical contact element 5a-5g by moving the associated respective third contact element 6a-6g radially against the spring force of the springs 7a towards the inner wall 15 of the housing 14 via the crank of the crankshaft 10b associated with it, thus effecting an open position.

[0055] The electromechanical switching arrangement 1 shown in Fig. 1 and 2 is part of a power distribution unit 16 of an electric vehicle with a two-part high-voltage battery 17 as an energy storage device.

[0056] Figures 3 and 4 schematically depict two embodiments of a power distribution unit 16 for a motor vehicle. In addition to the electromechanical switching arrangement 1, the two power distribution units 16 also include a relay 22, which can be installed in different configurations.

[0057] In the present embodiment, the first electrical connection area 2 is connected to the energy storage device, namely the battery pack, via its associated connection points 20 for the electric drive and several consumers of the vehicle. The second electrical connection area 3 is electrically connected to a charging infrastructure via its associated connection points 21.

[0058] Switching arrangement 1 is used as a passive control element. Switching arrangement 1 makes the necessary / required electrical connections before the circuit is closed. Only when the relevant electrical contacts are switched does relay 22 close and close the circuit. This ensures that any arcing that may occur during switching on is only handled by relay 22.

[0059] 2024P00065 WO When the circuit is interrupted, the sequence is reversed. Relay 22 first interrupts the circuit and extinguishes any arcing that may occur. Only then does switching arrangement 1 close / open the desired electrical connections.

[0060] In order for relay 22 to perform the active function of arc quenching, it can only be used at certain positions in the high-voltage path.

[0061] In Figure 3, relay 22 is installed between the high-voltage batteries 17 and the terminal 20 for the vehicle's drive system. Relay 22 is positioned upstream of the first electrical connection area 2 of the switching arrangement 1 in the current path leading from the high-voltage battery, such that the switching arrangement 1 is located between relay 22 and terminal 20.

[0062] In Figure 4, the relay 22 is located in the current path that runs from the terminal 20 towards the switching matrix 1, with the relay 22 again outside the switching matrix before the first electrical connection area 2.

[0063] For an architecture with two battery banks, each with a voltage of, for example, 400V, the two battery packs are shown in Figures 3 and 4.

[0064] In a first step, the switching arrangement 1 must connect and / or disconnect the required contacts by rotating the camshaft 10a. As long as the relay 22 is open, the movement of the camshaft 10a does not cause any current flow. The switching arrangement 1 therefore switches without a load.

[0065] Only when relay 22 is switched on does the current flow become independent of the required load: DC charging at 800V, DC charging at 400V, driving, or AC charging. To comply with the vehicle manufacturers' required fast switching sequences, it is necessary that relay 22 switches on immediately after the switching arrangement has been rotated into the desired position.

[0066] 2024P00065 WO General switching times of, for example, 500 ms require the entire process to be completed within this time: from turning the switching arrangement 1 to precharging a DC-Link capacitor in the inverter and closing the power path with the relay 22.

[0067] DC link capacitors are used, for example, in the intermediate circuit of a converter. Their main function is to buffer the DC voltage between the rectifier and the inverter, thus providing a temporary energy storage device.

[0068] When switching off or changing to another state, relay 22 must first interrupt the current flow before switching arrangement 1 closes / opens the necessary contacts. This ensures that switching arrangement 1 can switch without a load.

[0069] The only switching cycle of the power distribution units 16 in which a compensating current can flow via the switching arrangement 1 during switching is a switchover from a series 800V configuration to a parallel 400V configuration of the two battery packs 17a, 17b. Here, the current arising from a voltage difference does not flow via the relay 22.

[0070] In order to be able to switch without load here as well, it must be ensured that the two battery packs 17a, 17b are well balanced.

[0071] 2024P00065 WO reference character list

[0072] 1 Electromechanical switching arrangement

[0073] 2 First electrical connection area

[0074] 3 Second electrical connection area

[0075] 4a-4g First electrical contact element

[0076] 5a-5g Second electrical contact element 6a-6g Third electrical contact element

[0077] 7 Elastic element

[0078] 7a Spring

[0079] 8 actuator units

[0080] 9 Actuator

[0081] 9a Electric motor

[0082] 10 Shift shaft

[0083] 10a Camshaft

[0084] 10b Crankshaft

[0085] 11 Switching element

[0086] 12 Central longitudinal axis

[0087] 13 Cooling unit

[0088] 14 cases

[0089] 15 Inner wall (of the housing)

[0090] 16 Power distribution unit

[0091] 17 high-voltage battery

[0092] 17a, 17b Battery pack

[0093] 20 Connection point for electric drive

[0094] 21 charging port

[0095] 22 relays

[0096] X First level of construction

[0097] Y Second level of construction

[0098] 2024P00065 WO

Claims

1. Patent claims 1. Power distribution unit (16) with an electromechanical switching arrangement (1) having at least one first electrical connection area (2) and at least one second electrical connection area (3), wherein the first electrical connection area (2) has at least one fixed first electrical contact element (4a-4g) and the second electrical connection area (3, 3') has at least one fixed second electrical contact element (5a-5g), wherein the first electrical contact element (4a-4g) and the second electrical contact element (5a-5g) are electrically connectable and disconnectable via at least one movable third electrical contact element (6a-6g), and connected to a high-voltage battery (17) and a first connection point (20) for the electric drive and several consumers of the motor vehicle, the first electrical connection area (2) and a second connection point (21) are connected to the second connection area (3) of the switching arrangement (1).which is electrically connected to a charging infrastructure, characterized in that at least one relay (22) switches the electrical connection between the first connection point (20) or the high-voltage battery (17) and the first connection area (2).

2. Power distribution unit (16) according to claim 1 characterized in that the high-voltage battery (17) is designed in two parts.

3. Power distribution unit (16) according to claim 1 or 2, characterized in that the third electrical contact element (6a-6g) is biased into a switching position (A, B) via at least one elastic element (7) and can be actuated into at least one other switching position (A, B) via an actuator unit (8), wherein the actuator unit (8) has at least one actuator (9) and at least one switching shaft (10) which is movable via the actuator and, depending on the actuated switching position (A, B), moves the third electrical 2024P00065 WO The contact element (6a-6g) remains in the pre-tensioned switching position (A, B), or moves against the spring force of the elastic element (7) into at least one other switching position (A, B).

4. Power distribution unit (16) according to one of claims 1 to 3, characterized in that only the at least one relay (22) switches under load, while the contact elements of the switching arrangement (1) are unloaded.

5. Method for switching a power distribution unit (16), wherein in the switching arrangement (1) the necessary / required electrical connections are made, and only when the relevant electrical contacts are switched is the relay (22) closed and closes the circuit.

6. Method for switching a power distribution unit (16) wherein, to interrupt the circuit, the sequence is reversed and first the relay is opened and then the switching arrangement (1) switches the contacts. 2024P00065 WO

Images